Utilization of Torrefied and Non-Torrefied Short Rotation Willow in Wood-Plastic Composites

Area of Science:

• Materials Science
• Biocomposites
• Sustainable Materials

Background:

• Torrefaction is a thermochemical treatment process, primarily used in the energy sector.
• Torrefied biomass, such as wood, offers unique characteristics beneficial for developing advanced composite materials.
• Investigating torrefied wood's impact on polymer composites is crucial for sustainable material development.

Purpose of the Study:

• To evaluate the effects of torrefied shrub willow wood on the mechanical, thermal, and water absorption properties of polypropylene composites.
• To determine the influence of different torrefaction temperatures (225 and 300 °C) and weight percentages (5-40 wt%) of torrefied wood on composite performance.
• To assess the potential of torrefied wood as a filler in wood-plastic composites.

Main Methods:

• Short-rotation shrub willow was torrefied at 225 °C and 300 °C.
• Torrefied and non-torrefied wood particles were incorporated into polypropylene at various weight percentages (5, 15, 25, 40 wt%).
• Nine composite formulations were prepared via extrusion and tested for tensile, flexural, thermal degradation, crystallization, melting, and water absorption properties.

Main Results:

• Tensile properties remained unaffected by torrefaction levels.
• Flexural properties favored lower weight percentages of torrefied wood.
• The highest weight percentage of wood torrefied at 300 °C exhibited the slowest thermal degradation rate.
• Crystallization and melting temperatures of the composites were not significantly altered by the inclusion of torrefied wood.
• Water absorption significantly decreased with higher torrefaction temperatures and increased weight percentages of torrefied wood.

Conclusions:

• Torrefaction of wood significantly improves the water resistance of wood-plastic composites.
• Higher torrefaction temperatures and higher filler content lead to reduced water uptake.
• The study demonstrates the potential of using torrefied wood to enhance specific properties of polypropylene composites, particularly water absorption.